As conventional technology, there is a brush assembly applied to a six-pole magnet type DC motor disclosed in Korean Patent Application PCT/KR2013/007793.
The brush assembly is provided with brushes (three positive brushes and three negative brushes, for example) disposed on an outer periphery of a cylindrical commutator, and a box-shaped brush holder that holds the brushes.
The brush assembly is further provided with brush springs accommodated inside the brush holder to press the brushes to the commutator, positive connection plates for electrically connecting between the positive brushes, and negative connection plates for electrically connecting between the negative brushes.
The brush holder is disposed between the positive connection plates and the negative connection plates, and is assembled to both the connection plates from an inner peripheral side in a radial direction.
Methods of assembling the brush assembly according to the conventional technology (PCT/KR2013/007793) are considered to be according to the following two patterns.
1) In a state where the positive connection plates, all of the brush holders, and the negative connection plates are assembled, the brush springs and the brushes are inserted into the brush holder in this order from inside in a radial direction thereof.
Thereafter, a jig is inserted into a central portion of the brush holder so that the brushes do not drop out toward the inner peripheral side.
2) In a state where the positive connection plates and all of the brush holders are assembled, the brush springs and the brushes are inserted into the brush holder in this order from inside in a radial direction thereof.
Thereafter, in a state where a jig is inserted into a central portion of the brush holder so that the brushes do not drop out toward the inner peripheral side, all of the brush holders are fixed to the negative connection plates.
Since the brushes are inserted into the brush holder in a state of where at least all of the brush holders are assembled to the positive connection plates in the above assembling method, it is impossible to insert all the brushes to each brush holder from the inside in the radial direction simultaneously.
Moreover, when inserting all of the brushes into the brush holders one by one, it is necessary to press the brushes that have been inserted into the brush holders so that the brushes do not drop out toward the inner peripheral side.
Therefore, in the configuration of PCT/KR2013/007793, since assemblability of the brush assembly is poor and assembling work takes time, there is a problem that the productivity is low.